Electrical ignition system



F. CONRAD.

ELECTRICAL IGNITION SYSTEM. APPLICATION FILED FEB- 3. I9IO- RENEWED JAN. 8. I9I2- I 1,352,432, Patented Sept. 14,1920.

2 SHEETS SHEET I.

WITNESSES: INVENTOR Ia z aw M I BY ATTORN EY F. CONRAD.

I ELECTRICAL IGNITION SYSTEM. APPLICATION FILED FEB. 3, I910. RENEWED JAN. 8. I912.

1,352,432. 7 I Patented Sept. 14, 1920..

2 SHEETS-SHEET 2.

WITNESSES: I u I a %6@%% M ATTORNEY INVENTOR ,UNITED STATES PATENT OFFICE.

FRANK CONRAD, OF SWISSVALE, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELEC- I TRIO & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRICAL IGNITION SYSTEM.

- Specification of Letters Patent. Patent d S t. 14 1920' Application filed February 3, 1910, Serial No. 541,787. Renewed January 8, 1912. Serial No. 670,131.

To all whom it may concern Be it known that I, FRANK CONRAD, a citizen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented i new and useful Improvement in Electrical Ignition Systems, of which the following is a. specification.

My invention relates to systems of electrical'distribution that are adapted to supply current to the spark plugs of exploslon engines or to other ignition devices.

The object of my invention is to provlde a system of the character indicated by means of which a more reliable and effective spark for ignition purposes may be produced than can be produced bymeans hereto fore provided.

There are, in general, two different kmds of systems in use at present for supplylng current to ignition devices, the one comprising a source of current and aninductive resistance in series with'an interrupting spark plug, 2'. (2., one having separable terminals, and the other comprising a transformer or induction coil having its primary winding in series with a source of current and an interrupter, and its secondary windin connected to a spark plug having stationary terminals. The first system is objectionable because ofthe necessity of providing a movable terminal member in the engine cylinder, though it produces a hot reliable spark, and one that is particularly suitable for ignition purposes. While, in the second system, the terminals of the spark plug are stationary and the voltage between them is sufiicient to cause a reliable spark, the resistance of the secondary winding oi the induction coil or transformer is usuall so high that the amount of current permitted to follow a discharge is too small to cause a spark that is sufficiently hot and effective for ignition purposes.

Accordin and a high voltage is produced for causing a discharge between them, as in the second system above described, while in addition, the resistance of the circuit 1n which the plug is included is sufiiciently low to permit a large amountof current to follow the discharge. Thus, a hot, reliable and effective spark is produced, and it is seen that to the present invention, the terminals 0 the spark plug are stationary the present system embodies the advantages of both of the old systems, and is not subectto the disadvantages of either.

F i ures 1 and 2 of the accompanying drawmg 1 lustrate diagrammatically two systems that embody my invention.

InFig. 1, a magneto l, or other suitable generator or source of current, supplies energy to the primary winding 2 of a transformer or induction coil, an interrupting dev1ce comprising terminals 3 and 4 being included in circuit with the said winding. The interrupting device may, of course, be of any suitable construction-or type, but, as here indicated, it comprises, in addition to the terminals 3 and 4, a rotatable member 5 that is connected to the magneto-generator 1 so as to be driven synchronously therewith, and is provided with diametrically permitted to engage the terminal member 4 only when its outer end bears upon the flattened portions of the member 5. The interrupting device is preferably so adjusted that it interrupts the circuit of the primary winding 2 when the alternating electromotive force of the generator 1 is at its maximum value.

In -order that the interrupting device may effect prompt interruption of the circuit of the primary winding 2, a condenser 9 is connected between the terminals 3 and 4, to provide a shunt circuit through which all discharges may occur after separation of the said terminals, which discharges might otherwise occur between the terminals.

Also connected between the terminals of the generator 1 are a spark plug 6, or other ignition device, and the secondary winding 7 of the transformer or induction coil, a gap device 8 being included in circuit with the winding 7 in order that current may not be supplied thereto directl by the generator 1 or otherwise than in uctively.

In the operation of the system, the interrupting device 34-5 periodically interrupts the circuit including the primary winding 2 of the induction coil and thewinding 7, which discharges throligh the ecause gap device 8 and the spark plug 6.

of the disruptive discharge across the gap 8 and the effect of thecondensers 9 and 11, a high-frequency oscillating current is set up in the secondary circuit which breaks down or. ionizes'the air gap between the terminals of the spark plug 6. Of course{ plug 6 breaks down the high resistance of that portion of the circuit, and current from the generator 1, which is supplied directly, follows the discharge, it being noted that, at this time, the terminals of the interrupting device are separated, so that all of the generator current may, accordingly, be. supplied to the spark plug. The voltage of the generator 1 should be sufiicient to enable the generator to maintain the are between the terminals of the spark plug after it is started by the high voltage discharge from the secondary winding 7. i

The discharge of the secondary winding v7 cannot occur through the armature of the generator, because of its high inductance, and it is prevented from taking place through the primary winding 2 and the con-- denser 9 by the comparatively high inductance of the winding 2. In case this is not sufficient, an inductive resistance device 10 may be connected in series therewith, and, in order to provide a convenient path of discharge forthe voltageof the said device,

acondenser 11 should preferably be connected, as shown, between one of its terminals and the terminal member 8. Of course, the devices 10 and 11 may not always be found necessary or desirable.

When terminals 3 and 4 engage each other, the current of the generator 1 is diverted from the spark plug 6 into the primary winding 2, and the are between the terminals of the spark plug then becomes extinguished. The system continues its operation, in this manner, the spark between the terminals of the spark plug being alternately established and extinguished.

In Fig. 2 a battery 12 is substituted for the magneto-generator 1, in which case the member 5 may be driven by any suitable means, such as a part of an engine (not shown) in connection with which the ignition system is employ (1.

I claim as my invention:

1. An ignition system comprising a source of current, a primary circuit connected to the source, a secondary circuit that is inductively related to the primary circuit and includes a permanently ope'n gap in series therewith, and a. spark plug having its terminals connected both to the source directly and to the secondary circuit.

2. An ignition system comprising a source of current, a primary circuit including an interrupter, a secondary circuit that is inductively related to the primary circuit and includes a permanently open gap, and a spark plug having its terminals connected both to the source directly and to the secondar circuit.

3. n ignition system comprising a generator, "a transformer having its primary winding connected to the generator directly, an interrupter that is in .circuit with the primary winding and is operated synchronously with the generator, permanently separated terminals in series with the secondary winding of the transformer, and a spark plug having its terminals connected both to the generator and to the secondary winding of the transformer.

4. An ignition system comprising a source of current, a primary circuit connected to the source and including an interrupter, a

secondary; circuit inductively related to the to form an arc of low heat value and for supplying to the electrodes a current at relatively low voltage so as to form an arc of high heat value which follows after the arc of low heat value, comprising a source of current connected in circuit with the electrodes, a condenser and an induction coil having its primary connected to the condenser and' its secondary connected to the electrodes.

6. In an ignition system, spark electrodes, means for supplying to the electrodes a high-frequency current at a'high volta e 50 as to form an arc of low heat value and for supplying to the electrodes a current at relatively low voltage so as to form an arc of hi h heat value which follows after the are 0 low heat value, said means comprising a source of current connected in circuit with said electrode, a condenser with means for charging and discharging the same, and an induction coil with its primary connected to the condenser and its secondary con-- Ill 8; In an ignition system, the combination with a source of current, a primary circuit connected to the source, a secondary circuit that is inductively related to the primary circuit and includes a permanently open gap in series therewith, a condenser connected to said source, and a spark plug con-' nected both to the secondary circuit and directly to the source.

9. In an ignition system, the combination with a source of current of low voltage, of a circuit connected to said source and comprising stationary terminals having a gap normally impassable to the said current means for causing a disruptive discharge of current at high voltage across said gap,

whereby current from said source will also having a gap normally impassable to the said current, and means for causing said current to flow across said gap, said means comprising an induction coil'having rimary and secondary windings and stationary terminals having a permanently open gap in circuit with the secondary winding of said induction coil.

12. In an ignition system, the combination with a spark ,plug havin terminals with a gap between the same, 0 means for decreasing the resistance of said gap by effecting the discharge of oscillating current at high voltage across said gap and for causing a flow of current at low voltage to follow said discharge, said means comprising a circuit that includes stationary terminals having a gap between the same.

13. In an ignition system, the combination with a spark plug having electrodes with a gap between the same, of means,

comprising stationary terminals having an air gap between the same, for ionizing the medlum between said electrodes by .a discharge of oscillating current at high voltage and for causing a flow of current at low voltage to follow said discharge.

14:. In an ignition system, the combination with a spark plug having electrodes with a gap between the same, of means for causing a disruptive discharge of current at high voltage across said gap, said means comprising a circuit having stationary terminals with a permanently open air gap,

and means for causing current at low voltage to follow said disruptive discharge.

15. In an ignition system, the combination with a source of current at low voltage, of a spark plug having electrodes with a gap between the same that is normally impassable to said current, of means comprising stationary terminals having a gap between the same, for causing a disruptive discharge at high voltage between said electrodes and for causing current from said source of low voltage to follow said disruptive discharge.

16. An ignition system comprising a source, a primary circuit connected to said source, a secondary circuit inductively related to said primary circuit and including a permanently open gap, and a spark plu having its terminals connected both to said secondary circuit and, through low-resistance conductors, to said source.

17. An ignition system comprising a source of current, a primary circuit including an interrupter, a secondary circuit that is inductively related to the primary circuit and includes a permanently open gap, and a spark plug having its terminals connected both to said secondary circuit and, through low-resistance conductors, to said source.

18. An ignition system comprising a source, a primary circuit connected to said source, a secondary circuit inductively related to said primary circuit and including a permanently open gap, and a spark plug having its terminals connected both to said secondary circuit and, through noninductive conductors, to said source- 19. An ignition system comprising a source of current, aprimary circuit including an interrupter, a secondary circuit that is inductively related to the'primary circuit and includes a permanently open gap, and a spark plug having its terminals connected both to said secondary circuit and, through non-inductive conductors, to said source.

20. An ignition system comprising a source of current, a spark plug, means receiving current from said source for producing an oscillatory discharge to initially establish a spark at the spark plug, and connections between the source and the spark plug through which current received from the source is supplied directly to the spark plug following the initially established spark.

21. An ignition system comprising a source of current, a spark plug, means receiving current from said source for producing an oscillatory discharge to initially establish a spark at the spark plug, and other means for supplying current received from the source to the spark plug following the initially established spark.

22. In an ignition system, spark electrodes, a source of current having a connection with the electrodes to supply thereto a current to create an igniting arc, and means connected to the electrodes for supplying thereto a high-frequency current to create, at the air gap of the electrodes, a resistancereducing arc which is followed by the igniting are. '1

23. In an ignition system, spark electrodes, a source of current connected to the electrodes for supplying thereto a current of low voltage and of suflicient amperage to produce an arc of high heat value, and means connected to the electrodes for suppl ing thereto a high-frequency current of relatively low amperage and relatively high voltage so as to create an arc of low heat value and permit current from said source of current to establish the arc of high heat value.

24. In an ignition system, spark 616C", trodes, a source of current adapted to supply current thereto and establish an arc of high heat value, and means for supplying low amperage high-frequency current to the electrodes at high voltage so as to establish an arc of low heat value and reduce the 'resistance of the air gap between electrodes so that the arc of high heat value may be established by said source of current, said means comprising a condenser connected to the source of current and operatively related to the electrodes and devices for disruptively discharging the condenser.

25. In an ignition system, spark electrodes, a source of current connected thereto and impressing on the same a certain voltage, and means comprising a condenser and devices for charging and disruptively discharging the same for creating a highfrequency current, the condenser circuit being operatively related to the electrodes so that a high-frequency current is supplied thereto and an arc of low heat value is formed, said are serving to reduce the resistance of the air gap between the electrodes so that an arc of high heat value may be formed by said source of current.

In testimony whereof, I have hereunto subscribed my name this 31st day of J an., 1910';

FRANK CONRAD. Witnesses:

YASUDIRO SAKAI, B. B. Hrrms. 

